Method of controlling a drive system, a controller for controlling a drive system, a drive system and an assembly comprising a controller, a drive system and a permanent magnet synchronous motor
AssigneeCity University of Hong Kong
InventorsChunhua Liu, Senyi Liu
Life of this patent
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Abstract
A drive system is disclosed which applies to a six-phase integrated permanent magnet synchronous motor. The motor includes a set of six-phase half-bridge drive system and a thermistor monitoring system for monitoring the temperature of the six-phase half-bridge drive system. Aiming at the problem that the six-phase drive system is complicated and has many components, the invention adopts a grouping method to divide the six-phase drive system into two sets of three-phase drive half-bridges. To provide stability for long term operation, a thermistor is used to accurately measure the temperature changes.
Claims13
A method of controlling a drive system for an N phase permanent magnet synchronous motor, the motor comprising a rotor and a stator, the rotor comprising at least one permanent magnet and the stator comprising N windings, wherein N is an integer greater than 2, each winding comprising first and second ends;
- the drive system comprising:
- first and second power rails;
- a DC power supply of voltage Vdc connected between the first and second power rails;
- N bridge arms connected in parallel between the first and second power rails, each bridge arm comprising first and second switches connected in series;
- N output lines, each output line being connected between a first end of a winding and a bridge arm at a point between the first and second switches;
- each output line being connected to a different winding and a different half bridge arm;
- the method comprising the steps of for each of a plurality of consecutive duty cycles
- (a) providing the rate of rotation w of the rotor and a reference rate of rotation wref to a PI controller, the output of the PI controller being the q axis reference current iqref;
- (b) providing iqref and a measured q axis current iq to a PI controller, the output of the PI controller being the q axis reference voltage Uqref;
- (c) providing a d axis reference current idref and a measured d axis current id to a PI controller, the output of the PI controller being the d axis reference voltage Udref;
- (d) determining from a look up table the switch pattern for the next duty cycle, the output of the look up table being dependent upon Uqref and Udref;
- and;
- (e) setting the switches of the drive system at the end of the duty cycle to the determined switch pattern for the next duty cycle.
A controller for controlling a drive system for an N phase permanent magnet synchronous motor, the motor comprising a rotor and a stator, the rotor comprising at least one permanent magnet, the stator comprising N windings, where N is an integer greater than 2, each winding comprising first and second ends,
- the drive system comprising:
- first and second power rails;
- a DC power supply of voltage Vdc connected between the first and second power rails;
- N bridge arms connected in parallel between the first and second power rails, each bridge arm comprising first and second switches connected in series;
- N output lines, each output line being connected between a first end of a winding and a bridge arm at a point between the first and second switches, each output line being connected to a different winding and a different bridge arm;
- the controller comprising:
- (a) a first PI controller adapted to receive the rate of rotation w of the rotor and a reference rate of rotation wref and in response output a q axis reference current iqref;
- (b) a second PI controller adapted to receive iqref and a measured q axis current iq and in response output a q axis reference voltage Uqref
- (c) a third PI controller adapted to receive a measured d axis current id and and a d axis reference current idref and in response output a d axis reference voltage Udref;
- (d) a signal processor adapted to receive Uqref and Udref and determine a switch pattern for the switches of the drive system from a lookup table, the output of the look up table being dependent on Uqref and Udref, the signal processor further comprising an output for providing the switch pattern to the switches.
A drive system for an N phase permanent magnet synchronous motor, the motor comprising a rotor and a stator, the rotor comprising at least one permanent magnet and the stator comprising N windings,
- the drive system comprising
- first and second power rails;
- a DC power supply of voltage Vdc connected between the first and second power rails;
- N bridge arms connected in parallel between the first and second power rails, each bridge arm comprising first and second switches connected in series;
- N output lines, each output line comprising a first end connected to a bridge arm at a point between the first and second switches and a second end for connection to a winding;
- the N bridge arms being grouped into A groups of B bridge arms such that N=AB, each group of B bridge arms being a B phase inverter.
Dependencies are inferred from the claim text.